Digester for chemical treatment of substances.



No; 670,485. Patentad Mar. 26. I901.

B. S. SUMMERS.

DIGESTEB FOE CHEMICAL TREATMENT OF SUBSTANCES;

(Application filed July 28, 1898.;

(No Modal.)

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Units STATES BERTRAND S. SUMMERS, OF CHICAGO, ILLINOIS.

DIGESTER FOR CHEMICAL TREATMENT OF SUBSTANCES.

SPECIFICATION forming part of Letters Patent No. 670,4 5, dated March 0Application filed July 28, 1898 To all whom it may concern/.-

Be it known that I, BERTRAND S. SUMMERS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Digesters for ChemicalTreatment of Substances, of which the following is a full, clear,concise, and exact description, reference being bad to the accompanyingdrawings, forming a part of this specification.

My invention relates to a digester for the chemical treatment ofsubstances, my'objects being to provide means whereby a solution may bereadily transferred from one digester or vat to another, and,furthermore, to provide means whereby materials or substances in adigester may be successively subjected to several different solutions orchemicals without removal from the digester.

In accordance with my invention in the preferred form thereof twodigesters are employed connected by a system of piping,

whereby the solution may be passed from one digester to the other bycreating a difference of gaseous pressure between the two digesters, thepiping also accommodating the passage of two different liquids to andfrom the digesters. In order to effect the transfer of the liquid fromone digester to the other by gase-.

ous pressure, it is necessary to provide means whereby a maintaineddiiference of pressure may be employed, to thus effect the passage ofall of the liquid in one digester to the other digester. I preferablyprovide a heater in connection with each of the digesters, the heater inpractice taking the form of a steam-coil provided in the interior ofeach digester, to thus produce an excessive pressure which serves toforce the liquid from one digester into the other, digester, the coilsbeing connected with a steam-supply pipe, whereby steam may be admittedto either coil, to

thereby convert the liquid in the digester into Serial No. 687,110. lNomodel-J vation, partially in section. Fig. 2 is a plan view thereof.

Like letters refer to like parts in both figures.

The digesters d b are provided with covers a b, respectively, which canbe removed for theinsertion of the material to be treated and which arecapable of being locked in position to withstand pressure within thedigester. Upon the respective covers are provided the pressure-gages a17 thermometers a 19 and the valves a b Within the digester a is a coilof steam-pipes a connected by pipe a with a boiler or othersteam-supply, while a coil of steam-pipes b is provided within thedigester b and connected with the steam-supply by a pipe 12 In the pipesa and b are the valves 0, 19 The coils a and b are connected with anexhaust by means of pipes (1 b respectively. A pipe 0 extends betweenand connects the lower ends of the digesters and has two valves 0 c onopposite sides of a pipe 01 connected therewith and having connectedthereto a pipe 01, extending to a water tank or supply, and a pipe (1extending to an exhaust, valves (1 d being'provided in the respectivepipes. A pipe eextends from the pipe 0 and is connected with a pipe 6',extending to the steam-supply, and with a pipe 6 extending to a vacuumpump or ejector, valves e e being provided in the respective pipes.

The apparatus as above described, although applicable for variouspurposes, is particularly designed for the treatment of paperpulp,fibers, such as flax, and the like to permit the same chemical solutionto operate successively upon substances in the two digesters and,furthermore, to permit the access of a second liquid or solution to eachdigester after the first solution is passed therefrom. The solutionbeing in the digester a. and the pulp or other material being immersedtherein and the cover a secured in position, steam is passed through thecoils d to heat the solution to the proper temperature. At thecompletion of the operation when it is desired to transfer the solutionto the other'digester the valves 0 and e are opened, whereby a' vacuumis created within the digester b, and the valve 6 is then closed and thevalve 0 opened, whereby the digester b is placed in communication withthe digester a. The pressure within the digester CL and the vacuumwithin the digester I) create a difference of pressure which effects thetransfer of the solution from the digester ct to the digester b. Toassist the vacuum in effecting the transfer, the steam-pressu re in thedig-ester from which the liquid is removed may be employed, or thedigester from which the liquid is being removed may be connected withthe atmosphere by opening, for instance, the valve 01., in which casethe pressure of the atmosphere will assist the vacuum in effecting thetransfer. After the transfer the valves 0' and c are closed and steam ispassed through the coils b to heat the solution to the proper degree. Inorder to subject the paper-pulp or other material in the digester a tothe second liquid or solution, the valves 0, a, and d are opened and theliquid from a tank or other source of supply is admitted to the digestera, or where the liquid desired is water the valves e and 0 may be openedto admit steam to the interior of the digester, the steam beingcondensed therein by the admission of water through the valve a orotherwise to produce the liquid. After the liquidhas been conveyed tothe digester a steam may be passed through the coil a to heat the liquidto the desired temperature. At the completion of this operation thevalves 0 and 61 may be opened to permit the pressure within the digesterto force the liquid through the pipes 0,611, and d to the exhaust, or byopening valves 0 and d the liquid may be forced back into the tank. Thevalves are then closed, and when it is desired to convey the solutionfrom the digester I) back to the digester ot the valves 0 and e areopened to create a vacuum within the digester a, and then the valve 6 isclosed and the valve 0 opened to permit the solution to flow fromdigester b to digester a. At the completion of the operation upon thematerial within the digester the cover thereof may be removed to permitthe withdrawal of the material.

By the above construction the manual transfer of the flax or othermaterial operated upon from one solution to another is obviated, and thesolution itself is conveyed from one position to another, and thistransfer is accomplished by thepressures within the digesters, wherebythe necessity of manual interference except for operating the valves isobviated. By this construction, furthermore, the material to be operatedupon may be subjected successively to several liquids or solutionswithout removing the same from the digester, so that the material afterbeing placed in the digester remains therein until final completion.Thus the manual transfer of the material to be operated upon from onedigester to another, as well as the manual transfer of the solution, isavoided. The employment of two digesters, with means 'for transferringthe solution from one to the other, results in a great saving of laborand, furthermore, results in a saving of heat and energy, since thesolution is transferred from one digester to the other while at a hightemperature and without the necessity of cooling the liquid down, aswould be necessary were the liquid to be drawn from the digester andsubsequently returned to the same digester and again heated.Furthermore, as the solution is subjected to pressure it may be passedfrom one digester to the other without excessive lowering of thepressure, thereby saving the energy which would otherwise be required toraise the pressure to the required degree.

My invention may be applied to more than two digesters by duplicatingthe piping between the digesters. Instead of employing thesteam-pressure for moving the liquids compressed air or other fluid maybe employed, being admitted to the digester by means of the valves (L oHaving described my invention, what I claim as new, and desire to secureby Letters Patent, is

1. In combination, a pair of digesters or vats, a communication betweenthe same, and means for main taining a difference of gaseous pressurebetween the interiors of said digesters to force the liquid from onedigester to the other, substantially as described.

2. The combination with a pair of digesters or vats, of means foradmitting liquid at will to either digester, a heater for each of saiddigesters, a communication between the digesters, and means for forcingthe liquid from either digester to the other, substantially asdescribed.

3. The combination with a pair of digesters or vats, of removable coverstherefor, a communication between the same, means for subjeeting theinterior of either digester to an excessive pressure at will and meansfor creating a vacuum in either of said digesters at will, substantiallyas described.

4:. The combination with a pair of digesters or vats, of removablecovers therefor, means for admitting liquid to either of the digestersat will, a communication between the same, and means for creating avacuum in either of said digesters at will to force the liquid fromeither of said digesters to the other, substantially as described.

5. In combination, a pair of digesters or vats, a communication betweenthe same, and a heater for each of said digesters for producing asteam-pressure therein to force the liquid from one digester to theother, substantially as described.

6. The combination with a pair of digesters or vats, of removablesealing-covers therefor, a steam-heater for each of said digesters, apipe extending between said digesters, a pipe communicating with saiddigesters and leading to a vacuum-producer, a pipe communicating withthe digesters and leading to a source of liquid-supply, and valves forcon- IIO trolling the several pipes, substantially as described.

7. In combination, a pair of digesters or vats, a communication betweenthe same, and steam-coils provided in each of said digesters forconverting the liquid into steam in either digester to thereby create apressure for forcing the liquid from one digester to the other,substantially as described.

8. In combination, a pair of digesters or vats, a communication betweenthe same, a steam-coil in each digester, a steam-supply pipe connectedwith both of said steam-coils and a pair of valves one for controllingthe admission of steam to each steam-coil, substantially as described.

9. In combination, a pair of digesters or vats, a communicating pipebetween the same, a steam-supply pipe and a vacuum-pipe connecting withsaid communicating pipe and valves for controlling the passage throughsaid steam-supply and vacuum pipes, substantially as described.

10. In combination, a pair of digestersor vats, acommunicating pipebetween the same, a steam-supply pipe and a vacuum-pipe connectedtherewith, a steam-coil in each of said digesters connected with saidsteam-supcation between said digesters, and means for continuouslysupplying and maintaining an excess of gaseous or steam pressure in thedigester'from which the liquid is to be withdrawn to thereby force theliquid from either digester to the other, substantially as described.

In witness whereof I have hereunto subscribed my name in the presence oftwo witnesses.

BERTRAND S. SUMMERS.

Witnesses:

H, R. KINGMAN, W. CLYDE JoNEs.

